Epoxides serve useful roles as intermediates in biochemical pathways, but being chemically reactive, they also can produce deleterious effects such as alkylation of DNA and proteins, frameshift mutations, and tissue necrosis. In view of this the long range objectives of this work are 1) to determine the extent to which chemically reactive epoxide metabolites of drugs and xenobiotic materials are responsible for the damage which occurs to various tissues following administration of the epoxide precursor, 2) to elucidate the relationships between the chemical properties of the precursors and the metabolites, and their propensity to cause cellular injury, particularly hepatic necrosis and mutagenesis, and 3) to elucidate enzymatic mechanisms of epoxide metabolism and the eppxidediol pathway.